Safety switch-gauge



Dec. 17, 1963 F. w. MURPHY ETAL 3,114,903

SAFETY SWITCH-GAUGE Filed Jan. 2'7, 1961 ATTORNEYS I United States Patent ()fiice 3,ll4,903 Patented Dec. 17, 1963 3,114,9(93 SAFETY SWHTQHQAUGE ll ranl-r W. Murphy and Frank W. Murphy, in, both of 31311 S. Sheridan Road, Tulsa, Qkla. Filed .Tan. 27, W61, Ser. No. 85,342 2 Claims. (Qt. sis-ass This invention relates to a safety switch gauge, and has as its primary object the provision of an improved condition responsive safety switch and gauge contained in a single instrument which will be effective upon the achievement of a predetermined condition, such as a drop in pressure, a rise in temperature, or other unfavorable condition, first to actuate an alarm, either visual or audible in order to attract attention to the malfunctioning of the machine, and secondly, upon a further deterioration of the condition to which the mechanism is responsive to effectively shut down the motor or other mechanism.

An additional object of the invention is the provision of a switch gauge of this character which is reliable and eflicient in operation, sturdy and durable in construction, and relatively simple and inexpensive to manufacture, assemble, and utilize.

Still other objects reside in the combinations of elements, arrangements of parts, and features of construction, all as will be more fully pointed out hereinafter and shown in the accompanying drawing wherein there is disclosed a preferred embodiment of this inventive concept.

In the drawing:

FIGURE 1 is a front elevational view of the switch gauge of the instant invention, a fragment of a circuit associated therewith being schematically shown.

FIGURE 2 is an enlarged sectional view taken substantially along the line 2-2 of FIG. 1 as viewed in the direction indicated by the arrows; and

FEGURE 3 is a sectional view taken substantially along the line 3-3 of FIG. 2 as viewed in the direction indicated by the arrows, the face plate being broken away.

Similar reference characters refer to similar parts throughout the several views of the drawing.

As conducive to a clearer understanding of this invention, it may here be pointed out that there is a growing trend in all areas using industrial engines, to signal an alarm at a point safely above the danger point at which the equipment must be stopped, but at a point which indicates a tendency of the lubrication or cooling system or other correlated equipment toward failure. Heretofore, this purpose has been accomplished by the use of two separate safety switch gauges, one of which has been set at slightly below the desired operating pressure, or above the required water or oil temperatures. The other switch has been set at the absolute minimum or maximum points at which the equipment must be shut down. This obviously has called for two sets of instruments and double installation costs.

By virtue of the instant invention there is provided in a single installation a dual switch accomplishing the functions of both the abovementioned switches, in that upon the achievement of a predetermined low pressure or high temperature slightly below the desired operating optimum an alarm or signal is actuated, while upon a further deterioration of the condition concerned, the equipment is absolutely shut down.

By virtue of the instant invention the conditions to which the switch responds in both instances may be readily adjustable, while the contact indicating arms are clearly visible at all times on a calibrated dial on a single instrument.

laying reference now to the drawings in detail, the switch gauge of the instant invention is generally indicated at iii), and comprises a cylindrical casing 11 having a back plate 12, and suitable mounting screws 13 or the like carried thereby. The back plate 12 has associated therewith a pressure or temperature responsive element (not shown) contained in an enlargement 14, the switch and its actuating mechanism being generally of the type disclosed in my prior Patent No. 2,722,576. The condition responsive mechanism in turn actuates an operating rod id which engages a lug 16 carried by a U-shaped mounting member 17 which is pivotally mounted on a shaft 18 which extends between a back plate 19 and a dial plate 26 positioned interiorly of the casing. The bracket 17 carries at its extremity forwardly of the dial plate 20 towards the glass enclosed front 21 of the instrument a pointer arm 22, the latter carrying a contact sleeve 23. The pointer arm is biased in a direction opposite the bias of operating rod 15 by means of a spring member 24, the opposite end 25 of which is engaged by an upstruck portion 26 of the back plate 1?. Contact sleeve 23 is adapted, upon the achievement of a predetermined low pressure or high temperature, to engage a contact screw f-tl which extends through a threaded sleeve 31, which extends to the exterior of the casing, the screw being suitably adjustable in accordance with the condition to which it is desired to have the associated apparatus respond, and the adjusted position maintained by means of lock nuts 32. From contact screw 30 a wire 33 leads to an absolute cut-off switch in the circuit of wiring 35 leading to any desired operating mechanism, such as an internal combustion engine or the like.

The mechanism heretofore described has been substantially identical to that disclosed in my above-mentioned previous patent, it being noted that the dial plate 2% is provided with suitable indicia 36 on the face thereof, with which the tip of pointer indicator 23 coincides.

Dial plate 2%) has a relatively large opening 3'7, through which is visible 2. second pointer arm 38 having a contact sleeve 39 thereon. The pointer arm 38 has an offset portion 48, as best shown in FIG. 2, from which the indicating portion ll extends upwardly behind the dial plate 20, the forward portion 42 of pointer arm 38 being positioned between the dial plate 2t and the glass housing 21 and mounted at its lower extremity on the shaft 19.

A coil spring 45 surrounding shaft 15? serves to bias pointer 38 in a direction opposite the direction to which it is urged by operating lever 15, it being pointed out that at its lower portion pointer arm 38 has a projection 46 which is engageable by the transverse bight 17 of arm 22, the arrangement being such that movement of the arm 22 beyond the predetermined point by operating member 15 will carry the arm 33 therewith.

However, as the pressure drops, or the temperature in creases, contact sleeve 38 is adapted to engage the end of a contact screw 43 which extends through a threaded sleeve 49 in the wall of the casing, the screw being adjustable therein, and being held in position by means of lock nuts 5%.

From the outer end of contact screw 48 a wire 51 extends to an audible or visual alarm 52 from which a line 53 extends to any desired source of power. It is to be noted that in the preferential setting of the device the contact screw 48 is extended to a point materially beyond the contact screw fit? so that initial contact upon the achievement of a predetermined condition is effected by the contact sleeve 39. This serves to actuate the alarm 52 to call attention to the malfunction of the mechanism, prior to actual shut down in order to enable an operator to correct the malfunction without actually shutting down the machinery.

If, however, the deficiency is not corrected, and the condition still tends to deteriorate, the contact sleeve 23 will,

upon contact with contact screw 30, actuate shut down switch 34 to deactivate the associated mechanism.

A suitable reset mechanism, including an exteriorly operable push button 55 which extends through a sleeve 56 to actuate a lever 57, is also provided for reopening the circuit closed by the sleeve 23 and the contact screw 30. The end of the lever 57 seats in a notch 58 in arm 22 to hold sleeve 23 out of contact with contact screw 30 until the achievement of the desired temperature, pressure, or other condition within the apparatus has been achieved. At this time a spring (not shown) returns the lever 57 to an out-of-the-way position so that the device is reset and functions normally.

Such an actuating apparatus is shown more clearly in my above-mentioned Patent No. 2,722,576.

From the foregoing it will now be seen that there is herein provided an improved safety switch gauge which accomplishes all the objects of this invention, and others, including many advantages of great practical utility and commercial importance.

As many embodiments may be made of this inventive concept, and as many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative, and not in a limiting sense.

We claim:

1. In a safety switch gauge in which a pointer and scale provide an indication of a monitored condition in combination a casing, a shaft extending across said casing, a first pointer arm pivotally mounted on said shaft, a second pointer arm independently pivotally mounted on said shaft, a first contact member mounted at a predetermined location in the path of pivotal travel of said first arm to contact the first pointer arm upon the deterioration of a monitored condition and to prevent the movement of said first arm past the location in one direction of said first contact member, a second contact member mounted at a predetermined location in the path of pivotal travel of said second arm to contact said second arm upon the further deterioration of a monitored condition, first spring bias means for biasing said first pointer arm toward said first contact member, second spring bias means for biasing said second pointer arm toward said second contact member, means responsive to a monitored condition for positioning said second pointer arm in its range of travel, said second pointer arm including means to releasably engage said first pointer arm for positioning said first pointer arm away from said first contact member in its range of travel by said second pointer arm and for releasing said engagement with said first pointer arm responsive to the engagement of said first arm with said first contact member which prevents the arm from moving past the member, means responsive to the contact of said first contact member and said first pointer arm for sounding an alarm to indicate a deteriorating condition, means responsive to the contact of said second contact member with said second pointer arm for stopping the machine whose condition is being monitored.

2. The structure of claim 1 wherein said first and second contact members each comprises a screw, said screws being mounted in separate tubular interiorly threaded sleeves extending through the wall of said casing, and clamping nuts surrounding each screw for holding the same in said predetermined locations in the paths of pivotal travel of said first and second arms, respectively.

References Cited in the file of this patent UNITED STATES PATENTS 2,620,412 Ford Dec. 2, 1952 2,722,576 Murphy et al. Nov. 1, 1955 2,861,140 Woodall et al Nov. 18, 1958 2,880,286 Ferris Mar. 31, 1959 

1. IN A SAFETY SWITCH GAUGE IN WHICH A POINTER AND SCALE PROVIDE AN INDICATION OF A MONITORED CONDITION IN COMBINATION A CASING, A SHAFT EXTENDING ACROSS SAID CASING, A FIRST POINTER ARM PIVOTALLY MOUNTED ON SAID SHAFT, A SECOND POINTER ARM INDEPENDENTLY PIVOTALLY MOUNTED ON SAID SHAFT, A FIRST CONTACT MEMBER MOUNTED AT A PREDETERMINED LOCATION IN THE PATH OF PIVOTAL TRAVEL OF SAID FIRST ARM TO CONTACT THE FIRST POINTER ARM UPON THE DETERIORATION OF A MONITORED CONDITION AND TO PREVENT THE MOVEMENT OF SAID FIRST ARM PAST THE LOCATION IN ONE DIRECTION OF SAID FIRST CONTACT MEMBER, A SECOND CONTACT MEMBER MOUNTED AT A PREDETERMINED LOCATION IN THE PATH OF PIVOTAL TRAVEL OF SAID SECOND ARM TO CONTACT SAID SECOND ARM UPON THE FURTHER DETERIORATION OF A MONITORED CONDITION, FIRST SPRING BIAS MEANS FOR BIASING SAID FIRST POINTER ARM TOWARD SAID FIRST CONTACT MEMBER, SECOND SPRING BIAS MEANS FOR BIASING SAID SECOND POINTER ARM TOWARD SAID SECOND CONTACT MEMBER, MEANS RESPONSIVE TO A MONITORED CONDITION FOR POSITIONING SAID SECOND POINTER ARM IN ITS RANGE OF TRAVEL, SAID SECOND POINTER ARM INCLUDING MEANS TO RELEASABLY ENGAGE SAID FIRST POINTER ARM FOR POSITIONING SAID FIRST POINTER ARM AWAY FROM SAID FIRST CONTACT MEMBER IN ITS RANGE OF TRAVEL BY SAID SECOND POINTER ARM AND FOR RELEASING SAID ENGAGEMENT WITH SAID FIRST POINTER ARM RESPONSIVE TO THE ENGAGEMENT OF SAID FIRST ARM WITH SAID FIRST CONTACT MEMBER WHICH PREVENTS THE ARM FROM MOVING PAST THE MEMBER, MEANS RESPONSIVE TO THE CONTACT OF SAID FIRST CONTACT MEMBER AND SAID FIRST POINTER ARM FOR SOUNDING AN ALARM TO INDICATE A DETERIORATING CONDITION, MEANS RESPONSIVE TO THE CONTACT OF SAID SECOND CONTACT MEMBER WITH SAID SECOND POINTER ARM FOR STOPPING THE MACHINE WHOSE CONDITION IS BEING MONITORED. 